GC-MIP-PED as an element-specific system for the determination of organomercury compounds

The application of the combination of gas chromatography and a self-developed plasma emission detector for organomercury speciation is presented. The system, basing on interference filter technology, is described briefly. The plasma and the optical system have to be optimized to reach highest sensitivity for mercury detection. Dimethyl-, methyl- and inorganic mercury as selected compounds have been separated on a GC column and calibrated to obtain the analytical performance data of the system used. Finally, the analysis of some real samples has been performed.     

Reactions of indoles with mercury (II) salts

A number of mercurated indoles were prepared. Their spectroscopic data (UV,ir,^1H-NMR and13C-nmr) are reported. Our results contradict certain data appearing in previous reports on similar compounds. When heated in acetic acid mercurated compounds decomposed, although the products formed were not identical with those obtained earlier from the same substrates by the action of thallium(III) acetate in acetic acid. Reaction of l-methylindole-3-mercuriacetate with styrene in the presence of lithium tetrachloropalladate furnished a product which was tentatively assigned the structure 9-methyl-1,3-diphenyl-1, 2, 3, 4-tetrahydrocarbazole.     

Samarium(II)-induced coupling of acid chlorides with allylic halides

Samarium(II)-induced coupling of acid chlorides with allylic halides gave diallylated tertiary alcohols. Monoallylated allylic ketones could not be obtained.     

Photochromic long‐chain organomercury(II) dithizonate complexes in the azomethine series

The synthesis and characterization of a series­of 4 ‐ (4′‐ n ‐alkoxybenzylideneimino)phenyl‐­mercury<?tw=97.2%>(II) dithizonates, [C_nH_2n+1OC₆H₄CH­NC₆H₄Hg<?tw>(Hdptc)] (H₂dptc = 1,5‐diphenylthiocarbazone = dithizone; n = 1, 4, 12, 14 or 18), is described. The intermediate long‐chain organomercury(II) acetates were obtained by condensation of 4‐aminophenylmercury(II) acetate with the appropriate 4‐n‐alkoxybenzaldehydes. The thermal behaviour of the complexes was studied by polarized optical microscopy and differential scanning calorimetry but revealed no mesophases. All of the complexes, however, were reversibly photochromic (yellow ⇌ blue) upon irradiation of chloroform solutions with visible light, and the half‐lives of the metastable blue forms were substantially increased relative to that of the parent mercury(II) bis(dithizonate). The compounds were not photochromic in the solid state. Copyright © 2000 John Wiley & Sons, Ltd.     

Gas-chromatographic determination of organomercury(II) compounds

Gas chromatography has proved to be an invaluable technique not only for the identification and determination of organomercury(II) compounds but also for differentiating inorganically bound from organically bound mercury. It also offers a possible route for determining various inorganic species through their conversion into organomercury(II) compounds. These procedures and the chemical and instrumental problems associated with them are reviewed.     

Thermal Studies on Some Biologically Active Organomercury(II) Complexes

Thermal behaviour of a number of organomercury(II) complexes of the type, p-XC₆H₄HgCl(L¹) (I), p-XC₆H₄HgCl₃(L²) (II), p-XC₆H₄HgL³ (III) and p-XC₆H₄HgL⁴ (IV) [L ¹=isoniazid, L ²=theobromine, L ³=phenyldithiocarbamate, L ⁴=p-nitrophenyldithiocarbamate; X=Me, MeO, NO₂] has been investigated. From TG curves, the order and activation energy of the thermal decomposition reaction have been elucidated. The variation of the activation energy has been correlated with the nature of the substituent on the phenyl ring. The heat of reaction has been elucidated from DSC or DTA studies. The fragmentation pattern has been analysed on the basis of mass spectra.This revised version was published online in November 2005 with corrections to the Cover Date.A part of this work was carried out at Intitute of Microbial Technology, Chandigarh, under the Visiting Associateship Scheme (1992–95) of the Council of Scientific and Industrial Research, New Delhi.     

Chromatographic Separation of the Halides

Abstract

Column chromatography with the liquid ion exchanger Aliquat 336 was evaluated for the separation of the halides in aqueous solution. The separation was successfully accomplished by a gradient elution technique using 0.1 M sodium acetate and various concentrations of sodium nitrate as eluants. A comparison of two methods of column loading was made.     

Simple oxidative pretreatment for determination of organomercury by cold vapour atomic fluorescence spectrometry

A simple and rapid method has been developed for the direct determination of organomercury in toluene extracts. The oxidative pretreatment, intended for cold vapour-atomic absorption/fluorescence spectrometry, involves the use of bromide/bromate reagent under strong acid conditions. The pretreatment is performed directly in a volumetric flask and avoids the need for back extraction and phase separation. Recoveries for methyl mercury additions to toluene, at the 2 g/1 level, ranged from 100–106%.On leave Xianjiang Environmental Research Institute, Urumqui, Xianjiang Province, Peoples Republic of China     

Analytical Separation of Copper(II), Cobalt(II) and Nickel(II) Using Polymer Bound Anthrantic Acid

Abstract

The preferential complexing tendency of different nietal ions towards chelating agents anchored on a polymer has been used for separation of transition metals. the anthranilic acid group was anchored on the polymeric cellulose back-bone by successive coupling with trifunctional reagent cyanuric chloride, in diozane medium, at pH 7 and 9–10, respectively. This polymer bound chelating agent was used to separate copper(II), nickel(II) and cobalt(II) in the concentration range 1.0–0.1 mmol/L. the separation of a mixture of two components was quantitative using column chromatography.     

On the Reaction of Triphenyltrithiophosphites with Copper (I) and Copper(II) Halides

Abstract

Reactions of triphenyltrithiophosphite (PhS)₃P with copper (I) and copper (II) halides (CuHal, CuHal₂, where Hal=Cl, Br) have been investigated.     

The behaviour of different organometallic compounds in the presence of inorganic mercury(II): transalkylation of mercury species and their analysis by the GC–MIP–PED system

It is shown that four different mercury species are formed by the abiotic reaction of inorganic mercury with different, ecologically relevant, organolead and organoarsenic compounds. Therefore solutions of tetraethyl-lead, trimethyl-lead chloride and dimethylarsonic acid were prepared and mixed with stock solutions of inorganic mercury at different concentrations. The final solutions were analyzed for their content of newly synthesized mercury species. The analysis was carried out by using a system of solid-phase micro-extraction (SPME): capillary gas chromatography (GC), microwave-induced plasma (MIP) and a plasma-emission detector (PED). We found that transfer of one or two alkyl groups to the inorganic mercury is possible under the conditions mentioned below. The transalkylation rate depends on the kind of organometallic compound and on the pH. The results were confirmed by the reaction with inorganic mercury and analysis of a soil sample, containing tetraethyl-lead and trimethyl-lead, in which not only the monoalkyl compound, but also the dialkylated compound of the relevant inorganic metal, were found. © 1997 John Wiley & Sons, Ltd.     

Crystal structures of organomercury(II) derivatives of cyclohexanone and benzaldehyde thiosemicarbazones

The crystal and molecular structures of the organomercury(II) complexes [Hg(C₆H₅)(chtsc)], 1, and [Hg(C₆H₅C₅H₄N)(btsc)], 2, obtained from the reaction of phenylmercury(II) acetate with cyclohexanone thiosemicarbazone (Hchtsc) and that of [2-(pyridin-2′-yl)]phenyl]mercury(II) acetate with benzaldehyde thiosemicarbazone (Hbtsc), respectively, are described. Both 1 and 2 are monoclinic, space group C2/c. Complex 1 has a distorted T-shaped geometry {C-Hg-S, 161.91(10)°} and 2 can be considered to have a distorted seesaw geometry {C-Hg-S, 171.2(10)°}. In both complexes the ligands act as bidentate chelating anions bonding through azomethine N¹ and thiolato S atoms.     

Synthesis of aryl acetamides by aminocarbonylation of benzylic chlorides using carbamoylsilane as an amide source

Using N-methyl-N-(1-phenyl)ethylcarbamoyl(trimethyl)silane as an amide source, the direct transformation of benzylic chlorides into the corresponding aryl acetamides through palladium-catalyzed aminocarbonylation is described. The electronic property and the relative position of substituents on the aromatic ring impact the coupling efficiency.     

The Reduction of Organic Compounds with Chromium(II) Salts

Chromium(II) salts can be used for a variety of reductions in organic chemistry; for example, alkyl halides and suitably substituted olefins may both be reduced to alkanes, and alkynes may be converted into trans-olefins. Several epoxyketones are reduced to α,β-unsaturated ketones or β-hydroxyketones, and a nitro steroid was found to give a hydroxy(hydroxyimino) compound. The reduction of alkyl halides is reported to proceed by a free-radical mechanism; the halogen atom that is set free forms a bridge between two chromium atoms.     

Efficient homocoupling reactions of halide compounds catalyzed by manganese (II) chloride

A new efficient homocoupling reaction was reported in one pot by a combination of metallic magnesium and a catalytic amount of manganese (II) chloride. Various aromatic and alkyl halides underwent homocoupling smoothly, affording the corresponding symmetrical homocoupling compounds in moderate to good yields. The readily available MnCl₂, the mild reaction conditions and the operational simplicity and practicability allow for an easy and practical procedure for the purpose of carbon carbon bond formation. Copyright © 2007 John Wiley & Sons, Ltd.     

吸附柱分离-离子色谱法测定锑中微量硫

建立了吸附柱分离-离子色谱法测定锑样中微量硫的方法.方法采用王水,氢溴酸,浓HCl等试剂将锑样溶解,并使锑样中的硫转化为SO42-,低温加热蒸干,使锑完全挥发.然后在氧化铝柱上过柱,用氨水洗脱,最后将处理好的样品溶液注入离子色谱系统进行分析测定.优化了离子色谱操作条件,以流速为1.2 mL/min的3.5 mmol/L的Na2CO3与1.0 mmol/L的NaHCO3作为淋洗液,对标准液和样品溶液的测定,线性范围为0.2～100 μg/mL,检出限为0.2 μg/mL,回收率为92.9%～103.1%,该法适合锑样中微量硫的测定.     

Simultaneous determination of Cr(III) and Cr(VI) with prechelation of Cr(III) using phthalate by ion interaction chromatography with a C-18 column

Ion interaction chromatography has been successfully used for the simultaneous determination of Cr(III) and Cr(VI) in waste water. A C-18 column which had been dynamically coated with octylamine was used for the separation of Cr(III) and Cr(VI) based on anionic interaction. Cr(III) was chelated with potassium hydrogen phthalate (KHP) before injecting into the column since the Cr(III) did not exist in an anionic form like the Cr(VI) (Cr₂O₇²⁻) presented at the optimum condition. The analytes were detected at 200 nm and linear relationship between absorption with the concentration of Cr(III) or Cr(VI) was 0.1-50 mg/L. Most of the interested interferences including alkali metals, heavy metals and organic materials have no significant effect on Cr(III)-KHP complexation and Cr(VI) stability, only NH₄⁺ and ascorbic acid yielded the serious effect on the Cr(VI) stability. The relative standard deviations calculated from both of peak area and retention time were 0.75-2.20%. The sensitivity of the method at the level concentration of sub mg/L enabled the simultaneous determination of Cr(III) and Cr(VI) contents in waste water samples without any special sample preparation step.     

Synthesis and characterization of ciprofloxacin compounds with cadmium(II) and mercury(II) chlorides

Five new compounds of ciprofloxacin (CfH = C₁₇H₁₈FN₃O₃) with cadmium(II) and mercury(II) chlorides were synthesized. The compounds were characterized by chemical analysis, powder X-ray diffraction, pH-metric titration, UV spectroscopy, and thermal analysis.     

Separation of palladium(II) and platinum(II) chlorides by means of a guanidine resin

The preparation and properties of a new, weakly basic ion-exchanger containing suilonylguanidine as the active groups are described. Palladium and platinum chlorides can be quantitatively separated by this resin. Under certain conditions platinum does not react with the resin, whereas palladium is adsorbed and can then be eluted with 3 M hydrochloric acid.